All software developers, in whatever language and platform, whatever methodology, will realize that there is some software that they don't want to write and that already exists. However, there may be multiple artifacts that already exist and possibly do what the programmer needs to do. Developers that write their own software conventionally will use published artifacts as building blocks in writing code within a larger project, so as to avoid re-writing software which already exists.
Complicating the problem of using existing artifacts is the fact that issues can arise with these artifacts over time (e.g., security defects, license changes, potential infringement of intellectual property) that a user might wish to address, and the existing artifact might change during the course of the development of a piece of software and after the piece of software has been developed and released (e.g., the introduction of a new version of the artifact).